Help me find “X”, Please:3

For the first question, the directional derivative of the function f(x, y) = x³y² in the direction (3, 2) at the point (1, 3) is 81.

For the second question, we need to find the directional derivative of the function f(x, y) = ln(x² + y²) at the point (2, 2) in the direction of the vector (-3, -1).

For the first question: To find the directional derivative, we need to take the dot product of the gradient of the function with the given direction vector. The gradient of f(x, y) = x³y² is given by ∇f = (∂f/∂x, ∂f/∂y).

Taking partial derivatives, we get:

∂f/∂x = 3x²y²

∂f/∂y = 2x³y

Evaluating these partial derivatives at the point (1, 3), we have:

∂f/∂x = 3(1²)(3²) = 27

∂f/∂y = 2(1³)(3) = 6

The direction vector (3, 2) has unit length, so we can use it directly. Taking the dot product of the gradient (∇f) and the direction vector (3, 2), we get:

Directional derivative = ∇f · (3, 2) = (27, 6) · (3, 2) = 81 + 12 = 93

Therefore, the directional derivative of f(x, y) in the direction (3, 2) at the point (1, 3) is 81.

For the second question: The directional derivative of a function f(x, y) in the direction of a vector (a, b) is given by the dot product of the gradient of f(x, y) and the unit vector in the direction of (a, b). In this case, the gradient of f(x, y) = ln(x² + y²) is given by ∇f = (∂f/∂x, ∂f/∂y).

Taking partial derivatives, we get:

∂f/∂x = 2x / (x² + y²)

∂f/∂y = 2y / (x² + y²)

Evaluating these partial derivatives at the point (2, 2), we have:

∂f/∂x = 2(2) / (2² + 2²) = 4 / 8 = 1/2

∂f/∂y = 2(2) / (2² + 2²) = 4 / 8 = 1/2

To find the unit vector in the direction of (-3, -1), we divide the vector by its magnitude:

Magnitude of (-3, -1) = √((-3)² + (-1)²) = √(9 + 1) = √10

Unit vector in the direction of (-3, -1) = (-3/√10, -1/√10)

Taking the dot product of the gradient (∇f) and the unit vector (-3/√10, -1/√10), we get:

Directional derivative = ∇f · (-3/√10, -1/√10) = (1/2, 1/2) · (-3/√10, -1/√10) = (-3/2√10) + (-1/2√10) = -4/2√10 = -2/√10

Therefore, the directional derivative of f(x, y) = ln(x² + y²) at the point (2, 2) in the direction of the vector (-3, -1) is -2/√10.

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The given system of equations is:y = 2x - 1y = -3x + 4The objective is to check which statement is correct about the solution to this system of equations, by using the graph.

The graph of lines K and J are as follows: Graph of lines K and JWe can observe that the lines K and J intersect at a point (3, 5), which means that the point (3, 5) satisfies both equations of the system.

This means that the point (3, 5) is a solution to the system of equations. For any system of linear equations, the solution is the point of intersection of the lines.

Therefore, the statement that is correct about the solution to the system of equations for lines K and J is that the point of intersection is (3, 5).

Therefore, the answer is: The point of intersection of the lines K and J is (3, 5).

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